Tests: additional tests for ticket used/paid storage

Context

Follow up on !4841 (merged) with added tests wrt new Storage.Ticket_balance.Used_storage_space and Storage.Ticket_balance.Paid_storage_space.

Manually testing the MR

Part of CI:

dune exec src/proto_alpha/lib_protocol/test/integration/michelson/main.exe -- test "^ticket balance"

And

 poetry run pytest --regtest-reset tests_alpha/test_contract.py -k 'test_add_clear_tickets'

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR